Patent GB-337865-A (GB)
Title: Improvements in and relating to change-speed gearing
IPC: B23Q5/14
Filed: 1929-08-23
Abstract: 337,865. Heide, H. C., (Cincinnati Bickford Tool Co.). Aug. 23, 1929. Drilling-machines. - A changespeed gear has a single hand lever for selecting one out of eight speeds from a single speed drive by means of a slidable and rotatable shaft to which is fixed a sleeve carrying a number of gear segments co-operating with gearshifting racks., a yoke being movable axially with the shaft to engage the rack not being used and prevent accidental movement thereof. As applied to a radial-arm drilling-machine the gears are all arranged in the drill-head and comprise a first shaft 4, Fig. 1, driven through bevel gears from the shaft 3 journaled on the radial arms. Gears 7a, 7b, 8<a> and 8<b> are secured to the shaft 4 and may be engaged respectively by one of the gears 9<a>, 9<b>, 10<a> or 10<b> which are arranged in two gear units 9 and 10 splined to a second shaft 11. Rotation is transmitted from the shaft 11 to a third shaft 14 through either of the gears 12a, 12b secured to the shaft 11 and the corresponding gears 13<a>, 13b on a gear unit 13 splined to the shaft 14. The eight speeds of the shaft 14 may be multiplied into thirty-two speeds at the drill spindle 2 by means of gearing C which is not described in detail. The gear units 9, 10 and 13 are moved axially to engage the respective gears by means of yokes 45, 41 and 48 respectively. The yokes 45 and 41 are carried by slides 34 and 32, Fig. 2, guided by fixed rods 40, 44 and provided with racks alternatively engageable by a toothed quadrant 30 on a sleeve 28 secured to a shaft 26. The shaft 26 is moveable endwise to engage the quadrant with either rack, and when in the neutral position shown in Fig. 2 a second quadrant 29 on the sleeve 28 meshes with a rack secured to a vertical rod which carries the yoke 48. A hand lever 19 is pivoted to the shaft 26 at 25 and is provided with a ball-end 20. Fig. 1, constrained to move in an arcuate slot 23 in a casing 24 on the drill head 1. The opposite side of the casing 24 is provided with two H-shaped slots E, F, joined by a slot G, through which the free end of the lever 19 projects. In the position shown in Fig. 2, the lever lies in the slot G and in moving the lever to one of the slots E or F, the gear unit 13 is moved to one of its two positions. Movement of the lever 19 to the right or left along one of the slots E, F, removes the segment 29 from engagement with its rack and engages the segment 30 with one of the racks on the clutch operating slides 32, 34. The final movement of the lever 19 along one of the slots d, e &c. oscillates the segment 30 and moves one of the gear units 9, 10 to its required position, the eight speeds being controlled by the lever lying in one of the eight positions d<1>, e<1>, d<2>, e<2> &c. A yoke-shaped casing 50, embracing the ends of the sleeve 28 so as to move axially therewith, carries single teeth 53<1>, 54<1>, 55<1> and 56<1> adapted to engage the respective racks and prevent motion thereof when the segments are moved out of mesh therewith. A square pin 59 engages lugs on the casing 50 to prevent its rotation with the shaft. Excessive movement of the slides 32, 34 is prevented by transverse teeth thereon, lying outside the rack teeth and of greater length, which engage the teeth 55<1>, 56<1>, and excessive movement of the yoke rod is prevented by the gear unit 13 meeting a bearing-ring 58, Fig. 1, or by a pin 57, Fig. 2, meeting a bearing for the rod. The shaft 26 is held in its different angular positions by a notched segment 60 thereon and a spring plunger 65.